There's an ambiguity in the words "basis of morality." It might be about the natural history of morality, or it might be about its justification. The problem is that there's no good way to draw conclusions about one from the other. In particular, the history of morality doesn't tell us anything about whether our moral beliefs and practices are legitimate. Even more particularly, the question of how morality figured in reproductive success isn't a question about the correctness of moral conclusions.
Here's a comparison. When we consider a question and try to decide what the best answer is, we rely on a background practice of reasoning. That practice has a natural history. I'd even dare say that reproductive success is part of the story. But whether our reasoning has a natural history and whether a particular way of reasoning is correct are not the same. modus ponens (from "A" and "If A then B," conclude "B") is a correct principle of reasoning whatever the story of how we came to it. On the other...

Defeating Rommel's plan amounted to defeating Rommel because there was something Rommel was trying to accomplish and defeating his plan kept him from doing that. Stopping someone from carrying out their plans is a straightforward case of defeating someone. But evolution isn't something that stops God from doing what he was trying to do and so it doesn't "defeat" God. If we can show that evolution is true, we've defeated a view about God, but God isn't a view.
In fact, however, I think your question really is the one in your last sentence: does showing that evolution is true show that there's no God? The answer is somewhat controversial, but I'd say no. It shows that a particular view of God is not true, but it doesn't show that there's no God. There are plenty of believers who think that evolution is true and that nonetheless, there's a God. Maybe no reasonable notion of God can be consistent with evolution, but this isn't nearly as obvious as it's sometimes assumed to be.*
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You're right to be suspicious of the idea that we somehow "obstruct natural selection." That way of putting things assumes a dubious notion of "natural" and suggests that if we influence evolution (which we do) this is somehow a bad thing. As you point out, medicine and other human inventions are natural in a perfectly good sense: we are part of nature and we create these things. Of course, there are also perfectly good uses of the word "natural" according to which medicines, computers, cars and so on aren't natural. But whether something is "natural" in that sense and whether it's good or bad are two very different questions. So is the question of whether these "unnatural" things have a place in evolution.
Some people think that because we can manipulate our environment, evolution doesn't apply to humans. This is confusion. Natural selection is a matter of differences in how likely an organism is to reproduce because of features of the environment it finds itself in. Even if we shape the...

I think the answer is pretty clear and is implicit in things you've said. Yes: something dangerous can be beautiful. Tigers would be a widely-accepted example. "Dangerous Beauty" isn't just the name of a movie that got a 70% fresh rating on Rotten Tomatoes. It's an idea that's something of a cultural touchstone. Maybe the perception of ugliness evolved to keep us from danger, or maybe the story is more complicated than that. (I'd strongly suspect the latter.) But however things evolved , the concepts have long since come apart. If someone commented on the beauty of a tiger, and someone else tried to correct her on the grounds that tigers are dangerous, a blank stare would be an appropriate response. We find the appearance of tigers beautiful. They'd look the same way if, somehow, they magically became the protectors of humans. We also find their movements graceful; same comment. The second question you ask is whether non-dangerous animals that we find ugly might actually be beautiful. The...

Phrases like "child abuse" are most useful if they pack some punch. When we think of child abuse, what comes to mind are such things as deliberate acts of cruelty, gross neglect, causing serious bodily harm, and sexual molestation. All of those are clear cases of child abuse. Whether a child ends up obese, however, is a complicated matter. Two children might eat the same diet, and yet one might end up obese and the other not. Parents may have some control over their children's weight, but the decision that one's child will not become obese might not be easy to act on, and acting on it might have its own unfortunate side effects. This isn't to suggest that childhood obesity is trivial. But obesity is complicated. If it could be easily prevented, and if the way to prevent it was widely understood, then we might say that clear cases of "allowing" one's child to become obese count as a kind of child abuse. As it is, things aren't nearly so straightforward.

Others can correct me if I'm wrong, but I think the solution to the puzzle is straightforward: physicalism isn't the same as reductive materialism. Indeed, that's part of Dupré's complaint against Nagel: Nagel's view of materialism is narrow and outmoded. You might have a look at this section of the article on physicalism in the Stanford Encyclopedia of Philosophy, which distinguishes reductive and non-reductive varieties of physicalism.

I'm not convinced that we gain a lot here by talking about obligation; more on that below. However it's true: if you are unhealthy, then this makes at least a marginal difference to other people's health care premiums. That's one reason why it would be a good thing to try to stay healthy, even it we don't want to use the stronger language of obligation. Of course, it's just one among many reasons for trying to stay healthy, and almost certainly not the most important. Indeed, some of the other reasons (being able to care for your children, could be an example) might move us a lot closer to saying that you're obliged to stay as healthy as you can. Why the hesitation about call it an obligation? Though staying healthy is a good thing in general, there are many, many things that are each, considered one by one, possible for us, and that would make others better off if we did them. However, there are so many such things that it's not even remotely possible to do them all. This makes it pretty clear...

The first question is whether there's a fact to be explained. Do "pretty" birds typically have "pretty" songs? And do "ugly" birds typically have "ugly" songs? I'm no expert, but I'm betting not. Peacocks are usually considered attractive; their songs not so much. Swans are (conventionally, at least) beautiful; their honking (at least to my ears) isn't. Many people like the cooing of pigeons. But pigeons aren't usually seen as "pretty." I'm sure a real bird aficianado could multiply examples. Of course, there are also questions about whether "pretty" and "ugly" are objective notions. That's a big question, but you can no doubt see that it's relevant. But leave that aside. If your speculation were correct, it would be an interesting fact. What might explain it is something that it's very hard to say in the abstract. We'd need a lot more detail, but in any case there wouldn't be much reason to expect philosophers to come up with the best answer.

It's an interesting question, and to answer it, I'm inclined to turn things around. Let's start with what's clear: the fact that the rapist committed the rape seven years ago (supposing for the moment that this is the magic number) isn't a reason to let him off. In fact, the very way you pose the question makes the point. You ask about "the rapist" who committed "his crime" long ago. You've already take it for granted that we can say: this man is the one who committed the crime. And we can say it without worrying about how many cells have come and gone. So yes: there is something more -- or something other -- to the notion of a person than just the idea of a collection of cells. The something needn't be anything spooky. After all, a corporation can exist for a hundred years, even though all the people have changed and all the buildings and equipment it owns have gradually been replaced. Although saying exactly what sameness amounts to here is complicated, it won't call for talking about...

Because it didn't evolve in any other species. That wasn't very helpful. More to the point, it may not even be true. For all we can say for sure, other hominid species (perhaps Neanderthal?) had language, but didn't survive. In any case, the question of just why a particular trait did or didn't show up more than once in evolutionary history may not have any clear or uniform answer. The philosophical issue here, I suppose, might be whether the fact (if it is one) that as useful a trait as language only appeared in one species makes some sort of difficulty for the theory of evolution. Someone might claim: if the evolutionary picture really is correct, we would expect to see many species with this trait. Being neither a biologist nor a philosopher of biology, I can't say for sure. But I'm strongly inclined to suspect that this just isn't a good reading of evolutionary theory. Given the complexity of language-capable brains, what might be surprising is that the ability appeared even once. But it...